Web take-up mechanism



May 23, 1967 R. H. MACK 3,321,148

WEB TAKE-UP MECHANISM Filed Oct. 21, 1965 INVENTOR.

g RONALD H. MACK. BY

)lMMMM ATTORNEY.

United States Patent 3,321,148 WEB TAKE-UP MECHANISM Ronald H. Mack,Plymouth, Mich., assignor to Burroughs Corporation, Detroit, Mich.,acorporation of Michigan Filed Oct. 21, 1965, Ser. No. 499,885 Claims.(Cl. 242--67.2)

. This invention relates to web handling apparatus and, moreparticularly, to a web take-up mechanism which prevents the formation ofundesirable slack in the portion of an incrementally advanceable webthat lies between a platen and a take-up spool.

One object of this invention is to provide an improved mechanism formaintaining a webtaut as it is being incrementally rewound.

Another object ofthis invention is to provide a web rewind mechanismoperable in unison with the feeding operation of a platen to maintainthe web therebetween taut during the feeding of the web.

' Another object of this invention is to provide a preloadable rewindmechanism which, prior to the feeding ofthe web, removes residual slack.

A further object of this invention is to provide web rewinding drivemeans for applying torque to the take-up end of the Web in a greaterdegree than that necessary to remove slack generated by thefeedingoperation.

Other objects of the invention will become apparent from the followingdetailed description taken in conjunc-- tion with the accompanyingdrawings in which:

FIG. 1 is a spread perspective of a web handling apparatus embodying thefeatures of the invention; and

FIG. 2 is a similar view of only a portion of the apparatus showing theelements of the invention in a driven position,'the elements of FIG. 2being shown in a different position than in FIG. 1.

The subject web take-up mechanism is illustrated and described in theenvironment of an accounting machine of the type disclosed in UnitedStates Patent 2,629,549 assigned by Thomas M. Butler to the assignee ofthe present invention. The following portions of the Butler patent areparticularly directed to a suitable adjacent environment for thisinvention: Line spacing means-column 122, FIGS. 102 and 103 on sheet 51;line spacing power drive-- column 152, FIG. 150 011 sheet 72. Thoseelements of the accounting machine which are disclosed hereinafter aswell as the Butler patent are identified byreference numerals over 1000,as in the Butler patent; whereas, new elements disclosed herein aredesignated by reference numerals below 100.

The subject invention may be employed for rewinding a web 11, such as a"conventional roll of journal paper. The web 11 is initially wourid upona rimless supply spool 13 which is freely rotatable on rod 13a thereduced ends of which are received in laterallyspaced guide plates as 14within a paper carriage 1056 of theaccoun'tingmachine. The webis guidedfrom the supply spoolaround an incrementally rotatable platen 1057, andthereupon around a take-up or rewind spindle or spool 15 that iscoupledto and is positively driven from drive shaft 15a. In a mannerdescribed in detail in the Butler patent, the platen is driven and drawsthe web away from the supply spool. .As a result of such web feeding,the used portion of the web would accumulate and lie slack between theplaten and the rewind spool were it not for the subject take-upmechanism. l

Stated briefly, to advance the web 11a predetermined distance, power isapplied to a shaft 1694 which causes therotation of a camdisc 1706 aswell as a stud 1705 secured thereto. The stud 1705 impinge upon a bail1247 and drives it rearwardly. A curved arm 1241 has its lower endconnected to the bail 1247 and is pivoted about nism is with referenceto both FIGS. 1 and 3,321,148 Patented May 23, 1967 ice a shaft 1242which passes proximate thereto, such that the rearward motion of thebail 1247 causes the curved arm 1241 to turn counterclockwise about theshaft 1242. FIGS. 1 and 2 illustrate the change of position of theseelements.

A pawl 1238 is pivotally mounted near its midpoint to the other end ofthe curved arm 1241. The rearmost end of the pawl normally rests uponthe top surface of a bushing 1103 which is secured to one of a pair ofcarriage end plates1069. Asthe curved arm turns counterclockwise, thepawl is shifted forward and at the same time urged clockwise by atension spring 1260 attached near its rearward end. However, the pawl isnot free to pivot clockwise and into mesh with the teeth of a ratchetwheel 1230 until the forward shifting of the pawl causes its rearwardend to ride down the surface of the bushing 1103. Thus, there isprovided a delay between the initiation of the power stroke, via thecurved arm 1241, and the onset of the driving of the ratchet wheel1230.

The ratchet wheel1230 and the platen 1057 are fixed about a common shaft1081. As the web 11 passes around the platen, it is held in frictionalengagement therewith by biased rollers, not shown. Accordingly,incremental actuation of the pawl 123$ positively advances or feeds theweb a determinable distance toward the rewind spool 15;

Also secured to the curved arm 1241 is one end of a link 17 which,through that arm, is pulled forward during each power stroke. The link17 and the following elements combine to drive the rewind spool 15 toprevent the formation of web slack as theweb is being positivelyadvanced. The rearward end of the link 17 is pinned to the lower end ofa rewind idrive arm 19. The rewind drive arm -19is pivotable about astud 21 which is secured between the ends of the drive arm and one ofthe carriage end plates 1069. The upper end of the rewind drive arm issomewhat T shaped, has a leading edge 23, and a rearward extendingportion 25. A coil spring 27 is secured parallel tothe portion 25between its rearmost terminus and one end of a laterally extending stud29, which passes in front of the leading edge 23. In the normalposition, as shown in FIG. 1, the leading edge 23 of the rewind drivearm 19 is held against the stud 29 by the coil spring 27 which isthenunder slight tension.

The other end of the stud 29 is secured to a rewind feed pawl mountingblank 33 that is pivotally mounted upon a tie rod 35 which is securedbetween the carriage end plates1069. A rewind feed pawl 37 is rockablypinned to the mounting blank 33 in close proximity to a rewind ratchetwheel 39 and is biased against the periphery of the ratchet wheel by atension spring 41 extending between the pawl and the mounting blank. Therewind ratchet wheel 39 and a drive sprocket 43 are axially mounted upona sleeve 45 which is freely rotatable about the tie rod 35.

The rewind spool 15 carries a driven sprocket 47 which is coupled to thedrive sprocket 43 through a link chain 49. A spring biased brake arm 51is positioned proximate the periphery of the driver shaft 15a for therewind spool 15 and has a leading edge which impinges thereagainst. Arestoring spring 53 is secured between the lower end of the drive arm 19and the adjacent guide plate 14. In the driven position, shown in FIG.2, this spring is under considerable tension.

The following operation of this web take-up mecha- 2. As previouslystated, the curved arm 1241 is rotated counterclockwise during eachpower stroke and simultaneously shifts forwardly both the platen feedpawl 1238 and the link 17. The motion of the link 17 imparts a clockwisemovement to'the drive arm 19 about its pivot 21 which displaces theportion 25 of that arm rearwardly and applies a distending force to thespring 27. The spring 27 has considerable resilience and under certainoperating conditions to be detailed hereinafter, in lieu of distending,pulls the stud 29 rewardly in an arcuate path about the tie rod 35.

The arcuate translation of the stud 29 drives the pawl mounting blank 33and the biased pawl 37 clockwise and advances the ratchet wheel 39 inthat direction. The rotational energy imparted to the ratchet wheel isdirectly coupled to the drive sprocket 43 and thereupon is transferredvia the chain 49 to the driven sprocket 47. In this manner the rewindspool is incrementally advanced to take-up or rewind that portion of theweb that is being fed past the platen. Upon completion of the powerstroke, the spring 53 restores the platen feeding and take-up elementsto their normal position, as shown in FIG. 1. During restoration andprior to the next subsequent web feeding and take-up operation, thebrake arm 51 restricts counterclockwise unwinding of the spool 15 andthereby the formation of slack from the take-up end of the web.

The operational description assumes that the spring 27 does not distendand therefore merely transmits motion to the stud 29 as if the stud werefused to the edge 23 of the drive arm. Under proper working conditions,however, the following factors alter the above overly simplified mode ofoperation and enable the spring 27 to be part of a broken ordisconnecting linkage which elicits a mechanical coaction that removesany pre-existing web slack, rewinds the Web in unison with the advancingof the web from the platen, and maintains adequate Web tension duringits feeding to prevent the formation of web slack.

As shown in FIG. 1, and from the description of the relative positionsand operation of the platen pawl 1238 and its associated ratchet wheel1230 as well as the feed pawl 37 and its associated rewind ratchet wheel39, it should be apparent that the curved arm 1241 need be pivoted onlya small amount to impel the feed pawl 37 into the rewind ratchet wheel39 and thereby drive the rewind spool 15. However, a much greaterdisplacement of the curved arm is required before the pawl 1238 isinduced to actuate the ratchet wheel 1230 and advance the web past theplaten 1057. For this reason, the sprocket 43, via the chain 49 andsprocket 47, imparts an advancing torque or pre-loading bias to therewind spool 15 prior to the feeding of the web past the platen. Thisadvancing or augmenting torque is sufiicient to rotate the spool 15 andtake up any slack that might have formed subsequent to the prior webfeeding sequence. Although the web take-up mechanism is designed toprevent the formation of slack due to web feeding, external conditionsbetween power strokes could generate some slack intermediate the platenand the rewind spool. It is this slack which is removed by thepre-loading of the web take-up mechanism. Not only is the removal of anypre-existing slack completed prior to the initial advance of the web viathe pawl 1238, but necessarily, the preloading must be sufiicient totake-up more slack than normally might be expected. Accordingly, thetake-up linkage coacts such that the drive arm 19 attempts to drive thepawl 37 and the ratchet wheel 39 through an arc which, via the rewindsprocket 47, could place sufficient strain upon the web to cause it torupture. To obviate the latter condition without reducing the efliciencyof the mechanism, the coil spring 27 provides the disconnecting linkageaction once the tension on the web approaches an unsafe limit. This webtension creates a reverse torque which is applied from the rewind spool15 to the srocket 47, through the chain 49, and thereupon to thesprocket 43 and the ratchet wheel 39, to thereby hold immobile the feedpawl37. The immobility of the feed pawl fixes the position of themounting blank 33, the stud 29, and therefore the forward end of thecoil spring 27. With the forward end of that spring fixedly positionedand its opposite end being carried rearwardly by the rearward portion 25of the pivoting drive arm 19, the coil spring 27 distends, as shown inFIG. 2. In this manner, the drive arm 19 is temporarily decoupled fromthe stud 29 and the remainder of the linkage leading to the rewind spool15. Hence, the rewind spool is not over driven, the web is not ruptured,yet there remains sufficient tension on the web to prevent therecurrence of slack. It is to be recalled that to this point in time thepawl 1238 has not yet meshed with the ratchet wheel 1230.

The next step in the operation is for the platen 1057 to beincrementally advanced by its pawl and ratchet wheel and thereby for theweb to be fed toward the rewind spool 15. As soon as the web begins tobe fed, there is a reduction of the reverse torque upon the spool 15 andthe linkage leading back to the feed pawl 37. The reduction of thereverse torque returns mobility to the feed pawl, the mounting blank 33,and the stud 29. The latter is then pulled rearwardly by the distendedspring 27 and by the operational train previously described, causes therewind spool to be driven until the reverse torque on the web becomessufficient to again immobilize the feed pawl. Thus, the coil spring 27remains partially distended during the entire time the web is being fed,prevents the formation of web slack, and at the same time protects theweb fromrupture. Upon completion of the power stroke the elements arerestored to their initial positions by the spring 53.

Although not necessarily obvious from the figures, the pawls, ratchetwheels, sprockets, and shafts of the take-up and the platen feedmechanisms are designed such that the distance the web is advancedduring each power stroke is always less than the peripheral rotationaldistance of the rewind spool 15. Accordingly, as the diameter of therolled up web increases about the rewind spool, the coil spring 27 isforced into greater distention during both the pre-loading and thefeeding sequences. This cooperation of elements further insures theobviation of web slack between the platen and the rewind spool.

Though the detailed description of this take-up mechanism has been setin the environment of a particular accounting machine, it will beunderstood that this environment is not to be considered a limitationand also that variations may be made in the take-up mechanism withoutdeparting from the spirit and scope of the invention.

I claim: 1. Drive means for controlling the amountv of slack in theportion of a web lying between a web feeding station and a web rewindstation comprising:

power means coupled to the web feeding and rewind stations and actuatingthe rewind station in unison with the feeding of the web from thefeeding station,

rewind station pre-starting means coupling the power means to the rewindstation prior to the feeding of the web from the feeding station,

differential feed means coupling the power means to the rewind stationand urging that station to rewind more of the web than is being fed, and

disconnecting linkage means intercoupling the power means, thepre-starting means, the differential feed means and the rewind stationand interrupting the power transmission from the power means to therewind station whenever the slack is reduced beyond asafe limit.

2. A drive means according to claim 1 wherein:

. said rewind station includes an incrementally driveable rewind spool,and

said pre-starting means includes a closely coupled pawl and ratchetwheel rotatably linked to the rewind spool.

3. A drive means according to claim 2 wherein:

said disconnecting linkage means includes an elongated tension memberhaving one end connected to the power means and the other end connectedto the pawl.

4. A web winding mechanism comprising:

a platen coupled for rotation to an incrementally actuatable ratchetwheel and pawl, peripheral contact of the web about the platen enablingthe incremental advance of the web during rotation of the platen,intermittent power means having a finite power stroke coupled to thepawl,

pawl restraining means delaying the engagement of. the pawl with itsassociated ratchet wheel, and thereby the advancing of the web past theplaten, until an intermediate point in the power stroke,

a web receiving spool,

web winding power transmission linkage connected to the power means,

said power transmission linkage including a pivotable drive arm, a windpawl coupled to said pivotable drive arm, and a ratchet member normallydelivering winding torque from the onset of the power stroke through theratchet member to the web via the receiving spool,

said transmission linkage receiving reverse torque from the web via thereceiving spool whenver the winding torque places an excessive amount ofstrain upon the web, and resilient disconnecting linkage meansintermediate the drive arm and the wind pawl actuated by the reversetorque and thereupon decoupling the drive arm from the wind pawl.

5. A web winding mechanism according to claim 4 further comprising:

torque augmenting means interconnecting the wind pawl to the receivingspool throughout the power stroke and coacting with the disconnectinglinkage means.

6. In a system which requires the incremental feeding of a web from apassive source, around a platen in frictional engagement therewith, andthen upon an intermittently driven Web receiver, the portion of the weblying between the platen and the web receiver being taken up by thereceiver until a predetermined tautness is obtained, a web take-upmechanism comprising:

an arcuiately advanceable drive arm,

an incrementally rotatable element positively coupled to the webreceiver, and

an elongated, resilient member connected between the drive arm and therotatable member and coupling the motion of the drive arm to the webreceiver through the rotation of the rotatable member for actuating theweb receiver to take up the web until the predetermined tautness isobtained,

the web receiver being coupled back to the resilient member whenever theweb becomes too taut, forcing a distention of the resilient member andthereby decoupling the motion of the drive arm from the web receiver.

7. In a system according to claim 6 platen advancing means, and

power stroke means common to the platen advancing means and the drivearm,

the platen advancing means including delay means intermediate the powerstroke means and the platen for delaying the application of the powerstroke to the platen until after the web receiver takes up the web andforces the distention of the resilient memher. 8. In a system accordingto claim 7: drive motion augmenting linkage coupling the rotatableelement to the web receiver and over driving the web receiver withrespect to the feeding of the web by the platen advancing means andforcing the distention of the resilient member during the application ofthe power stroke to the platen. 9. Means for controlling the amount ofslack in a web passing through an accounting machine comprising:

a freely rotatable web supply spool; an intermittently driven rewindspool; an incrementally advanceable platen intermediate the path of theweb from the supply spool to the rewind spool, the advancing of theplaten drawing the web from the supply spool and tending to create slackin the web proximate to the rewind spool; intermittent drive meanscommon to the platen and the rewind spool actuating them in unison andobviating the formation of web slack proximate to the rewind spool;rewind spool pre-loading means coupled between the drive means and therewind spool, applying driving torque thereto prior to the incrementaladvancing of the platen, and placing the web under tension; drivingtorque augmenting means including differential feed means coupling thedrive means to the rewind spool and placing the web under increasedtension; and web tension responsive drive coupling and decoupling meansconnected between the drive means and the rewind spool; the web tensionresponsive means including an elongated, pretensioned, distendablememher, the distention of which is controlled by the tension of the webproximate the rewind spool, excessive tension transmitted through therewind spool forcing the distention of the member and the decoupling ofthe rewind spool from the drive means. 10. Slack control means accordingto claim 9 wherein the intermittent drive means and the pre-loadingmeans include:

first and second pairs of pawls and ratchet wheels, reciprocatinglinkage simultaneously applying drive power to both said pawls, and pawldetaining means inhibiting the first pawl from coacting with its ratchetwheel until the second pawl has transmitted a portion of the drive powerto its associated ratchet wheel.

References Cited by the Examiner UNITED STATES PATENTS 7/1919 Lockwood242-67 12/1941 Anderson 242-67 X

1. DRIVE MEANS FOR CONTROLLING THE AMOUNT OF SLACK IN THE PORTION OF AWEB LYING BETWEEN A WEB FEEDING STATION AND A WEB REWIND STATIONCOMPRISING: POWER MEANS COUPLED TO THE WEB FEEDING AND REWIND STATIONSAND ACTUATING THE REWIND STATION IN UNISON WITH THE FEEDING OF THE WEBFROM THE FEEDING STATION, REWIND STATION PRE-STARTING MEANS COUPLING THEPOWER MEANS TO THE REWIND STATION PRIOR TO THE FEEDING OF THE WEB FROMTHE FEEDING STATION, DIFFERENTIAL FEED MEANS COUPLING THE POWER MEANS TOTHE REWIND STATION AND URGING THAT STATION TO REWIND MORE OF THE WEBTHAN IS BEING FED, AND DISCONNECTING LINKAGE MEANS INTERCOUPLING THEPOWER MEANS, THE PRE-STARTING MEANS, THE DIFFERENTIAL FEED MEANS AND THEREWIND STATION AND INTERRUPTING THE POWER TRANSMISSION FROM THE POWERMEANS TO THE